1. Field of the Invention
The present invention relates to a power socket to be mounted on a radio, a tape recorder, a video camera or the like.
2. Description of the Invention
FIGS. 6 and 7 show a conventional power socket disclosed by Japanese Utility Model Publication No. 60/20308 (Japanese Utility Model Registration No. 1627076).
This power socket includes a hollow housing 100 to be mounted on a circuit board (not shown); a cover 110 mounted on the housing 100; a pin 120 having a plug connection portion 121 and a terminal portion 122 molded in an L-shape; and stationary and movable contact pieces (not shown). In the housing 100, the plug connection portion 121 of the pin 120 and the stationary and movable contact pieces are arranged in the height direction of the housing 100, i.e., the direction B at a right angle to a direction A along the surface of a circuit board (not shown) at the time when the power socket is mounted thereon.
More specifically, the cover 110 is mounted on the housing 100 at the rear end thereof. The cover 110 and a rear wall 101 of the housing 100 respectively have pin insertion holes 111 and 102, in which the plug connection portion 121 of the pin 120 is pressingly inserted. The terminal portion 122 of the pin 120 projects toward the circuit board. The terminal portion 122 is engaged with an L-shape engagement fixing body 130 formed on the cover 110. The housing 100 is provided at the lower portion thereof with an opening 103 adjacent to the rear wall 101. The stationary and movable contact pieces inserted from this opening 103 are disposed in a space 104 communicating with the opening 103. Terminals 141, 142 extending from the contact pieces are guided to the outside of the housing 100 through respective notch-like concave portions 105, 106 formed in the housing 100. These terminals 141, 142 project toward the circuit board. The cover 110 or the projection piece 112 is pushed to these terminals 141, 142. This causes the contact pieces to be fixed to the housing 100.
In the power socket having the arrangement above-mentioned, when a plug (not shown) is inserted in or removed from the plug connection portion 121 of the pin 120, the movable contact piece is displaced by the plug. This causes the movable contact of the movable contact piece to be separated from or come in contact with the stationary contact of the stationary contact piece, so that the contacts are opened or closed.
Recently, an electric machinery such as a radio, a video camera or the like is required to be made in a compact design, yet assuring a variety of functions. It is therefore required to mount, with a considerably high density, a variety of electric or electronic components on a circuit board. In this connection, a power socket is also strongly required to be made in an extremely compact design by minimizing the outer dimensions thereof.
However, it is difficult to reduce the outer dimensions (more specifically, the depth size) of the conventional power socket above-mentioned for the following structural reasons.
As a first reason, the plug connection portion 121 of the pin 120 and the stationary and movable contact pieces are disposed in the housing 100 in the direction B at a right angle to the direction A along the surface of the circuit board. Due to such an arrangement, in order that the terminal portion 122 of the pin 120 projects toward the circuit board it is required that the boundary corner portion a between the plug connection portion 121 and the terminal portion 122 of the pin 120 is positioned rearward (upward in FIGS. 6 and 7) of the rear ends of the stationary and movable contact pieces. Otherwise, the terminal portion 122 of the pin 120 which projects toward the circuit board, comes in contact with the stationary or movable contact piece. That portion of the plug connection portion 121 of the pin 120 which projects inside of the housing 100, has a predetermined length which cannot be shortened without any restriction. Accordingly, to assure a suitable position of the corner portion a, the length of the plug connection portion 121 is inevitably relatively lengthened.
As a second reason, the cover 110 is inevitable as a member for pushing the terminals 141, 142 of stationary and movable contact pieces so that the contact pieces are secured to the housing 100. Accordingly, it is not possible to adopt the arrangement where the engagement fixing body 130 is formed directly on the housing 100 with the cover 110 eliminated. Thus, the entire depth L' of the power socket becomes equal to the total sum of the depth D' of the housing 100, the projection height H' of the engagement fixing body 130 and the thickness T' of the cover 110.
In the conventional power socket having the arrangement above-mentioned, due to the requirements that the length of the plug connection portion 121 of the pin 120 should be lengthened and the cover 110 is inevitable, great restrictions are imposed on the arrangement to shorten the entire depth L' of the power socket to make the same in an extremely compact design.